| 摘要 |
A method and apparatus for detecting the presence of speech telecommunications tones on a communication line includes a voltage divider for ranging signals received from a communication line, a C-weight filter which receives the ranged signals and simulates the frequency response of the human ear to noise, an RMS-to-DC converter for producing a DC signal from the output of the C-weight filter, an A/D converter for converting the DC signal into digital data and a microprocessor for receiving the digital data and controlling the invented apparatus. Energy samples obtained from an accessed telephone line are, in software, assigned various weights in accordance with the level of energy found in each sample. The microprocessor, under software control, uses the weights actually assigned to determine whether the energy sampled is due to speech or a tone.
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